High-pressure compressors with variable set blades are known, in which compressors each blade root is fitted into a self-lubricating bushing assembled in a ring.
More particularly, as represented in FIG. 1, ring 1 (only an inner part of the ring is represented) comprises, on its inner surface, a circumferential groove 2 and a plurality of radial bores 3. A bushing 4 is positioned in each radial bore 3 and a blade root (not represented) is fitted into each bushing 4.
As represented in FIG. 2, each bushing 4 presents a cylindrical part 5 in which is fitted the blade root and a base 6 comprising two substantially parallel opposed sides 7 that engage the sides 8 of the circumferential groove 2 of the ring 1.
In operation, each blade is rotated by a variable setting device usually formed by an annular actuator (not represented).
The orientation of blades of a high-pressure compressor is particularly desirable when one wishes to position the blades at a given angle. Such positioning enables the blade positioning to be adapted to the engine speed.
In addition, to enable the assembly of each bushing 4 in the circumferential groove 2 of ring 1, a clearance is present between sides 7 of the base of bushing 4 and those of the circumferential groove 2.
A disadvantage of this type of bushing 4 resides in the fact that the clearance present between sides 7 of the bushing and those of the circumferential groove prevents the rotation of bushing 4 from being quickly and completely blocked 4 during orientation of the blade. In fact, during orientation of the blade, a rotation force is inevitably transmitted from the blade to the bushing 4. This bushing 4 rotation results in numerous contacts between the edges 9 of bushing 4 and the sides 8 of the circumferential groove 2. Eventually, these contacts result in premature wear of the sides 8 of the circumferential groove 2 or even perforation of the sides.